Mounted abrading wheels



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@pih. 1111i 1 H MILLER ET AL MOUNTED ABRADING WHEELS Filed June 22, 1955 HENRY E. M I LLEW VERNMIL. L SHEETS wv MTORNEYS MOUNTED ABRADING WHEELS Henry E. Milier, Chicago, IlL, and Vernal L. Sheets, Valparaiso, Ind, assignors to Chicago Wheel & Manu facturing Co., Chicago, 111., a corporation of Ilhnois Application June 22, 1955, Serial No. 517,276 3 Claims. (Cl. 51-206) This invention relates to mounted abrading wheels.

Abrading wheels that are formed of finely divided abrasive material bonded by conventional procedures and molded in a suitable fashion to the desired shape are quite well known, and in the manufacture of abrading wheels of this kind it is common practice to mold the wheel with an opening for receiving a mandrel on which the abrading Wheel is to be carried. The ordinary method of securing the mandrel to the abrading wheel is by a cement, and it will be appreciated that this cement must be exceptionally strong.

Abrading wheels of the foregoing kind are subjected to high torque and impact stress under many circumstances, such that the abrading wheel tends to work loose from the mandrel. This is particularly common where the abrading wheel is applied to a surface that produces extreme vibration or chatter of the abrading wheel, and as was mentioned, the common practice is to resort to a cement for securing the wheel to the mandrel. This has been accomplished by placing a quantity of the cement in the mandrel-receiving opening or bore in the wheel followed by the insertion of the mandrel, and if desired the mandrel itself prior to being inserted in the bore of the abrading wheel may be dipped in the cement and used as a swab. It will be appreciated that the diameter of the mandrel-receiving opening in the abrading wheel cannot be very much larger than that of the mandrel, because if the mandrel is to be accurately aligned with the axis of the wheel and not tip substantially from a truly centered relation during the setting of the cement, the bore of the Wheel and the mandrel disposed therein nited States Patent 0 must be relatively close fitting. As a consequence, the 1 amount of the cement that can be used is not great, and

therefore must be exceedingly strong, and one of the primary objects of the present invention is to enlarge the cemenbreceiving capacity of the bore of an abrading wheel without increasing the diameter of the bore or de- 1 creasing the diameter of the mandrel.

Another problem that has been encountered in mounted abrading wheels of the foregoing kind is that after prolonged periods of use the stressesthat were encountered produce weakening of the cement that holds the wheel to the mandrel, and a further object of the present invention is to reduce the stress to which the aforesaid cement is ordinarily subjected.

Specifically, the object of the present invention is to form the mandrel of a mounted abrading wheel with juxtaposed, circular grooves at the end that is to be inserted in the bore of the abrading wheel, and to provide the inner or driving end of the mandrel with fiat faces adapted to engage or seat in a key-way at the inner end of the mandrel-receiving bore of the abrading wheel. The grooves thus afforded greatly enlarge the cement-receiving capacity of the bore in the wheel, and the flat faces at the end of the mandrel disposed in the aforesaid keyway lessen the torque stress on the cement since the wheel will be rotated primarily by the fiat faces of the 2 key of the mandrel rather than by the shaft or shank portion of the mandrel bonded to the abrading wheel.

Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawing which, by way of illustration shOWs a preferred embodiment of the present invention and the principle thereof and what we now consider to be the best mode in which we have contemplated applying that principle. Other embodiments of the invention embodying the same or equivalent principle may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the purview of the'appended claims.

in the drawings:

Fig. l is a perspective view of an abrading wheel mounted on a mandrel in accordance with the present invention;

Fig. 2 is an exploded view of a mandrel and the abrading wheel in separated or dismounted relation, the abradin g wheel being shown in half-section;

Fig. 3 is an enlarged elevation of the driving end of the mandrel; and

Fig. 4 is an elevation similar to the mandrel is rotated through The present invention is illustrated in Fig. l as embodied in a mounted abrading wheel 10 which is formed of finely divided abrasive particles such as abrasive ceramics or the like that are molded and bonded together in accordance with known practice, and since the precise composition and method of manufacture of the abrading wheel constitute no part of the present invention itwill be recognized that such may be selected of any desired formulation and procedure. The abrading wheel 10 is mounted on a steel mandrel 11 in a way to be described hereinafter, and the mandrel 11 at the end opposite that mounted in the wheel 10 is adapted to be driven by the chuck of a power toolin the usual way.

To mount the abrading Wheel 10 to the mandrel 11, the wheel 10 is molded in the axial center thereof with a circular bore or mandrel-receiving opening 15,, and this bore will be of slightly larger diameter than the diameter of the mandrel 11. This difference may be but several thousandths of an inch since it is necessary that the mandrel 11 and wheel 10 be accurately centered as was mentioned above.

Under the present invention, the portion of the mandrel 11 that is to be received in the bore 15 is machined or otherwise formed with a plurality of uniformly spaced apart grooves 16, and because the mandrel 11 is circular in cross section these grooves will necessarily be of true annular shape. The grooves 16 will be separated by uniformly dimensioned annular ribs or ridges l8, and these ribs 18 will have the same outer diameter as the portion of the mandrel. 11 that extends beyond the bore 15 of the abrading wheel 10. Thus, to produce the grooves 16 it is merely necessary to select a piece of stock material for the mandrel, and to turn the stock piece down where it is desired to produce the grooves as 16.

Further in accordance with the present invention, the inner end of the mandrel is milled or otherwise provided with flat faces 11F so that in effect a square or rightangular driving key 11K is afforded at the end of the mandrel opposite that to be received in the chuck of the power tool. Preferably, the grooves as 16 are provided prior to providing the flat faces 11F, since so to do also provides at least one groove 161 at the driving end of the mandrel as shown in Figs. 3 and 4, and this groove will be defined by segments 181 of the ribs 18 that result from milling out the faces 11F. Thus, when the fiat faces 11F are provided as by milling or a like opera tion, to remove substantial quantities of metal at the driv- Fig. 3, except that ing end of the mandrel 11, portions only of the ribs as 18 and the grooves as 16 will remain.

The bore in the wheel 10 at the inner end is formed with a key-way 20, that terminates at a dead end within the body of the wheel 10. The opposed faces 29F of this key way are fiat't' 'ened so as to be complimentary to the ill ffities liF-bf the key 11K of the mandrel 11. The key-way Zil th'u's term will include forwardly facing shoulders 205 which will be engaged by corresponding shot-riders 113 at the driving end of the mandrel 11.

The aforementioned g'rodves as 16 and 16-1 in the mandrel 11 constitute annular recesses in which significaiit 'ciuant or the cemen't us'ed to hold the mandrel to the wheel 21 be retained. Thus, in contrast to the unifofrh diam tei on the ex osed portion of the mandrel 11, 1, the groove 16 enlarge the cement receiving "capacity" offhe bore 15, and in like manner the grooves or recess 16-1 on the key 11K enable an increased amount of cement to be utilized in the key-way 20. We have found that the following cement produces excellent res'tiitsi Polyester Resin (low molecular weight) "cc" 25 Activated Charcoal s t gin 0.3 Micro-sized Silica e gm 0.5 250 Mesh Flint gm 28.0

I Low molecular weight polyester resin is liquid in its natural state, as is well known, and is typified by the Laminac class of resins (viscosity 65-70 'poises) marketed by the A'me'riCanCyanamid Company. Resins of room temperature after about twenty-four hours. Howeve by the use of an e en smaller amount of catalyst and an oven cure fat 300 Ethe 'resinwill set completely in ap r'oiiimately'ISihinuteS.

The cement, apartfrorn the catalyst, can be placed on the shelf in "a sealed container, and just prior to use the catalyst is added. The purpose of the charcoal is to adsorb the resin so thatthere' will be no tendency for the resin to be absorbed by the abrading wheel. The filler is re resented by'th'eflint, and the finely divided silica substantially'in flour form is intended to fill the voids between the larger size "flint particles.

The primary advant'ageot'the foregoing cement is that there sin is promoted directlyto a rigid state while setting in the presence of'th'e catalyst or activator and does not pass through an intermediate liquid state as is common withtnan' of there'sin cements heretofore used for'inountii'ig anabradingwheel to a mandrel. Thus, the disadvantage of the aforementioned liquid intermediate state isthat if the mandrel has been trued in the bore of the abradi'ng wheel, the mandrel will tip when the cement passes through the intermediate liquid state during the course of the cure.

Where a room temperature'cure, rather than an oven cure is'us'ththe 'amount'of'catalyst is about 'one per cent 4 based on the weight of the polyester resin. Where an even one is used, however, less of the catalyst is necessary, and this amount Will depend of course upon the curing temperature preferred.

The cement to which the catalyst has just been added may be worked up with a spatula, and after this preliminary step has been performed, a selected amount of the cement may be picked-up on the mandrel, and the mandrel then inserted in operative position in the bore 15 of the abrading wheel. In about forty minutes, the cement is sufficiently set to hold the mandrel in a true-d position.

A small amount of the cement will be extruded resulting in a rim 25, Fig. 1, of cement about the base of the exposed portion of the mandrel 11, but because of the grooves 16 substantial quantities of the cement will be trapped in the bore 15.

Of particular importance in the present instance is that by having resort to a key as 11K, the amount of torque stress on the cement will be greatly reduced, and as a consequence, the effective life of the abrading wheel is materially increased.

Hence, while we have illustrated and described the preferred embodiment of our invention, it is to be underst'o'od that this is capable of variation and modification, and we therefore do not wish to be limited to the precise details set forth, but desire to avail ourselves of such changes and alterations as fall within the purview of the following claims.

We claim:

7 1.. A mounted Wheel for abracling comprising an abrading 'whe'e'l formed with a bore for receiving a mandrel, the inner end of said bore including a key-way of reduced size defined by a pair of parallel spaced apart flat faces, a mandrel of circular cross-section mounted in said here and having at the inner end a key of reduced size defined by flat faces fitting in to said key-way, a plurality of spaced apart annular cement-receiving grooves formed about a portion of said mandrel that is mounted in said bore, 'said'key also including a groove, and cement in at least some of said grooves holding the mandrel to the wheel.

p 2. A'm'andrel of circular cross section for an abrading wheel including a plurality of spaced apart annular grooves formed about a portion of the mandrel inwardly of one end, the end of said mandrel adjacent said grooves being provided with flat faces affording a driving key for the abrading wheel.

3. A mounted wheel for abrading comprising an abradirig wheel formed with a bore for receiving a mandrel, the inner end of said bore including a key-way, a mandrel of circular cross-section mounted in said bore and having at the inner end a key fitting in to said key-way, a'pluralityof spaced apart grooves formed in the portion of said mandrel that is mounted in said bore, said key also including a groove, and cement in at least some of said grooves holding the mandrel to the wheel.

No references cited. 

